Andrew Erueti, Amnesty's researcher-advisor on indigenous people's rights, has told Radio Australia's Asia Pacific a promised Land Commission to restore Pahari to their lands in the Chittagong Hills is not operational.

"Fifteen years have passed, it's been set up, there's bricks and mortar, members have been appointed, but it hasn't made a single determination on this lands issue," Mr Erueti said.

"While we continue to have uncertainty about land rights, the Pahari continue to be displaced.

"What we're asking the government of Bangladesh to do, is to make this a top (priority)."

Mr Erueti says the Land Commission process needs to be supplemented by other measures that provide reparations for displaced people who are unable to be restored to their land.

There may be cases also where it would be fair and just for settlers to be compensated, for those who're determined by the Land Commission that they can't remain on their lands," he said.

"Say, it's just impossible to go back to the lands because there's infrastructure built upon it, perhaps it's unsafe to go back, because it's polluted, who knows?"

Mr Erueti says many Bengali settlers are from disadvantaged backgrounds and are coming to the Chittagong Hills because of river erosion and changes in environment.

"We can see that Bengali settlers might move to the Chittagong Hill Tracts because it might offer more promise from where they currently live," he said.

"At the same time, we need to recognise that Bangladesh has human rights obligations that are owed to Pahari in relation to their traditional lands, and they need to be respected and recognised."

Mr Eruiti says the issue needs to be addressed promptly.

"We're setting up, basically, the grounds here for continuing tensions which we think can only escalate," he said.

"It's an urgent issue for Bangladesh to set up this Land Commission and to address these claims."